On the basis of preliminary results of last Sunday's congressional election in Mexico, the distribution of seats in the Chamber of Deputies would be as follows: PRI, 237; PAN, 143; PRD, 71; PVEM, 21; PT, 13; PANAL, 9; C, 6.

PRI's estimated total is composed of 183 deputies elected by first-past-the-post (including 46 in coalition with PVEM) and 54 by proportional representation; normally, PRI would be entitled to 79 list seats, but in that case the party would end up with a total of 262 seats, or 52.4% of the total number of deputies. However, according to the Constitution of Mexico no party can be awarded a proportion of Chamber seats exceeding its nationwide vote proportion by more than eight percentage points, disregarding invalid ballots or votes cast for parties with less than two percent. By having obtained 39.5% of the votes cast for the seven parties with at least two percent of the vote, PRI can only elect 237 deputies, that is 47.4% of the seat total.

Meanwhile, seat estimates for PVEM and PT include four and three first-past-the-post deputies, elected in coalition with PRI and Convergencia, respectively.